Our current projects - Page 2 - Videokarma.org TV - Video

ChuckA · #16 11-25-2002, 05:46 PM

Steve,

Looks like your mirrors have gone south. I have 4 of these sets and the flat mirrors are usually dull from many years exposed to the air, and not much can be done to bring them back. If you haven't already done it, cleaning the curved mirror in the housing can help a great deal, most of the ones I have have been in good shape just lots of dirt. Just don't rub very hard.

I think it was Rob who posted a good description and adjustment procedure for these Schimdt optic systems.

Chuck

Charlie · #17 11-25-2002, 06:08 PM

Steve,

The chassis in that set looks easy to work on... dealing with one chassis per section. Do the different pieces plug into each other, or are the wires from one chassis to the next soldered into one another?

Charlie · #18 11-25-2002, 08:26 PM

I put partial juice and later full juice to the Zenith 24MC32 chassis. The tubes all light up, but I found it has no B+ voltages. It uses silicon rectifiers, and they seem to have taken a dump. Now I'll have to make a trip to the parts house. Sure wish it used 5U4's... I have plenty of those laying around!

***Eric H*** · #19 11-25-2002, 11:59 PM

Charlie, my 56 Zenith portable uses the same construction on it's chassis.

So easy to recap, just heat the terminal from the top and pull the cap out, shove a new one in the hole and add a little solder!

I have a bunch of Compactrons that were going to hit eBay, let me know if you need any and I'll see if I have it.

Eric

Steve K · #20 11-26-2002, 09:14 PM

Chuck:

The mirrors have been cleaned but the curved one is ok but not perfect. The mirror in the lid looks perfect but to me it looks like a standard mirror. Should that one be mirrored on the surface like modern projection sets? If so where do I get one?

Charlie:

The seperate chassis plug into one another. There are about as many cables and plugs as capacitors! The chassis are not hard to work on but two of them have three to four can electrolytics each. I'm too lazy to take them out, cut them open and restuff them so I must somehow cram the new caps under the chassis. Sarnoff would roll over in his grave if he saw how it looks now but it works. I would probably do it more neatly if I were rebuilding it for someone else.

Steve K

ChuckA · #21 11-26-2002, 10:15 PM

Steve,

Both mirrors are front silvered. The spherical can be re-silvered by H.L. Clausing in Skokie, IL. (http://www.clausing.com/main.html)

The flat mirror I've been told is not a candidate for re-silvering due to size and age, best bet here is a thin rear surface mirror you can get at a local mirror shop.

I'm restoring a Berkshire Regency and have had the spherical mirror re-silvered and I have a new mirror from a modern HD set to replace the flat mirror.

Chuck

ChuckA · #22 11-28-2002, 07:27 AM

Here'a a shot of what happens when the project is bigger than a boxcar. I had to bring the test bench to the TV to troubleshoot & align the receiver from the RCA Berkshire TV.

Hope to start on the TV section next.

Chuck

jshorva65 · #23 01-16-2003, 09:43 AM

Hello all!

I've been extremely busy lately. Had a hectic Holiday season, working on several customer-requested restorations, still developing and producing reproduction parts, attempting to find time for some refresher business management classes, seeking some help from local Community Development agencies in getting loans for financing some big projects (my guitar and hi-fi amp lines, and the vintage tv replicas I've been asked to develop by a few friends in the furniture business). To get a jump on the project and get my design skills back into practice, I've been attempting to create drawings similar to the ones John Vassos must have created when he designed the 621TS. Eventually, I want to build replicas of several pre-war and a few post-war sets. The project is in its infancy at the moment, but I've managed to reconstruct some of the basic geometry of the 6211TS cabinet based on its relationship to the space that its chassis and picture tube occupied. Here's a preliminary sketch generated from the complex 3D vector model I'm creating. It's nowhere near finished, but gives some indication of what I'm attempting to do.

jshorva65 · #24 03-14-2003, 11:05 AM

I decided to take a few days off from customers' restorations to look into one from my own collection. This is an RCA 8T241 from eBay that was in pretty good electrical shape, so I decided to tackle it as a mini-vacation. I just had a "tough dog" case involving a Bendix with a badly damaged I.F. transformer and no available replacement that I had to pack up and ship home unfinished. Here's a shot of the 8T241 after the initial testing. The set has picture and sound after re-forming the electrolytics, checking for bad paper caps and replacing two I.F. tubes. I'll turn it on and post a pic of it running that 5" test CRT later today.

Rob · #25 03-14-2003, 02:22 PM

John,

Are you planning to replicate the vintage chassis on the prewar sets too or put modern guts in the repro vintage cabinet?

I had a 8T241 that had a trashed cabinet and used it as a source for a 10BP4 that I needed for another set, my first, the 1948, 10" floorstanding bakelite Admiral consolette. This RCA chassis also sourced a vertical blocking transformer for the Admiral which had one with an open winding.

Rob

rcaman · #26 03-14-2003, 04:18 PM

hi everyone. i have a lot of parts i also have some i.f. transformers
flybacks. if is something i think i wont need i will gladly sell or trade to one of the members of this forum. i have a lot of picture tubes also. steve

jshorva65 · #27 03-14-2003, 05:11 PM

Here's the 8T241 chassis running a 5" test CRT. I also replaced C76 and C77 in the grid circuit of the Vertical Output tube because they showed marginal test results on the Sprague TO-4. Replacing those caps made it easier to get good linearity and sufficient height at the same time, which was a little tricky with the old caps.

About the pre-war replica sets, they'll probably have a modern TV chassis inside simply because I doubt that some of the more exotic parts would be available. If I could afford to make my own parts, I'd definitely love to put a line of replicas into production with all-tube chassis' and RF-type HV supplies disguised in shells that resemble the old "killer" HVT's.

Charlie · #28 03-14-2003, 05:22 PM

John,

What's with the interesting safety glass in front of the crt and chassis?

jshorva65 · #29 03-15-2003, 09:36 AM

Quote:

What's with the interesting safety glass in front of the crt and chassis?

Charlie,

That's a subtle reminder from the author of the graphics software that I've been trying out that it's time to fork over some cash or pick another program. Actually, it's a pretty neat little program so I might just invest the 30 bucks or so and buy it.

John

jshorva65 · #30 03-15-2003, 11:14 PM

Well, I had a little setback with the 8T241 today. I put it back in the cabinet last night and watched it for about 2 hours with no problems, but today the picture was intermittently blacking out. with accompanying "screeching" noises coming from inside the HV cage. I shut it down and discharged the HV lead to the chassis, but didn't get the usual spark from the stored HV in the doorknob cap. OK, I thought that maybe the doorknob cap that was good yesterday might have suddenly failed, but it threw a healthy spark when I discharged it directly at its terminal. That left only one possible culprit, so I decided to have a look under the HV rectifier socket at the 1-Meg, 1-Watt resistor between the the HV rectifier / doorknob cap and the corona ring / CRT anode. Bingo, that resistor was open. I need to go get some 1-Meg/1-Watt resistors on Monday.